Olmesartan medoxomil, which is an angiotensin II receptor antagonist, is useful as an active ingredient in medicaments for treatment and prophylaxis of hypertension (for example, Patent documents 1 to 5 and Non-patent documents 1 and 2).
Olmesartan medoxomil is produced from olmesartan with the steps described below, and it has been desired to obtain novel crystals of trityl olmesartan medoxomil, which is a precursor of the final product, in order to improve operability and achieve an efficient production of a high-purity final product.
